China National Pharmaceutical Group (Sinopharm) will need to assess results from overseas Phase III clinical trials to decide whether its two-shot Covid-19 vaccine should be followed by a booster shot, a company executive said on Sunday.
Regulators and vaccine developers are looking at whether booster doses are necessary amid concerns that emerging variants of the new coronavirus might weaken protection of vaccines designed against older strains.
Antibodies triggered by Sinopharm's regular vaccines last about six months based on clinical trial data, Zhang Yuntao, vice president at China National Biotec Group (CNBG), an affiliate of Sinopharm, said on Sunday.
"The preliminary results so far showed that the booster vaccination can effectively increase the neutralizing antibody titer and antibody persistence, and also effectively improve the vaccine's ability to resist mutations," Zhang said at a news conference.
"Is a booster shot needed? When will the booster be given? The answer should be based on the results of future phase III clinical studies," Zhang said.
Antibodies triggered by two Covid-19 vaccine products from Sinopharm both have "pretty good" neutralising effect on variants found in Britain and South Africa, Zhang told a news conference, citing results from lab tests using blood samples taken from clinical trial participants.
Lab testing was ongoing for variants found in Brazil and Zimbabwe, Zhang said.